Pouch film and secondary battery including the same

ABSTRACT

Embodiments of the present invention provides a pouch film. In manufacturing a secondary battery, a gas may be generated when reacting an electrode assembly with an electrolyte. After the generated gas is discharged, the pouch film may be sealed. In this case, a deformation part may be formed in the gas chamber section which serves as a passage for discharging the gas, specifically, in the gas chamber passage, thus to prevent the electrolyte from flowing backward and maintain shapes of the gas chamber inlet during injecting the electrolyte.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.16/702,041 filed on Dec. 3, 2019, which claims priority to Korean PatentApplications No. 10-2018-0155380 filed on Dec. 5, 2018 in the KoreanIntellectual Property Office (KIPO), the entire disclosure of which isincorporated by reference herein.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a pouch film and a secondary batteryincluding the same.

2. Description of the Related Art

In modern society, the demand for secondary batteries is rapidlyincreasing across the industry such as a mobile device or an automobile,and studies into the secondary battery are actively conducted.

The secondary battery includes an electrode assembly and a pouch filmfor housing the electrode assembly. The secondary battery ismanufactured by forming a space to house the electrode assembly in thepouch film, then housing the electrode assembly in the space, followedby injecting an electrolyte and sealing the pouch film.

During injecting the electrolyte into the electrode assembly and thenperforming pre-charging, a gas may be generated. The gas generatedduring the pre-charging has to be discharged. The reason is that thesecondary battery may swell if the gas is not discharged, which isdisadvantageous in terms of strength or stability.

In this regard, the electrolyte may be injected through a gas chamberprovided in the pouch film and the generated gas may be discharged to anoutside. However, since the pouch film is prepared by mainly using ametal material having excellent elongation, it is difficult for thepouch film to maintain its original shape during injecting theelectrolyte. In addition, when rapidly injecting the electrolyte intothe pouch film, a case in which the electrolyte flows backward may alsooccur. Therefore, the need for a pouch film that helps to safelymanufacture the secondary battery arises.

PRIOR ART DOCUMENT Patent Document

-   (Patent Document 1) Korean Patent Laid-Open Publication No.    10-2018-0071799 (published on Jun. 28, 2018)

SUMMARY OF THE INVENTION

It is an object of embodiments of the present invention to provide apouch film that maintains an entire structure of a pouch in a process ofinjecting an electrolyte, or the like, thus to provide convenience inthe process.

In addition, another object of embodiments of the present invention isto provide a pouch film having a structure that allows an electrolyte tobe uniformly impregnated by inducing a flow of the electrolyte wheninjecting the same.

Further, another object of embodiments of the present invention is toprovide a pouch film having a structure for maintaining shapes of a gaschamber inlet for injecting an electrolyte and a portion adjacentthereto.

To achieve the above objects, according to an aspect of the presentinvention, there is provided a pouch film including: a housing sectionconfigured to provide a space in which an electrode assembly is housed;and a gas chamber section formed integrally with the housing section andconfigured to discharge a gas generated by reacting an electrolyte withthe electrode assembly to an outside, wherein the gas chamber sectionincludes a gas chamber inlet formed on one side thereof so that theelectrolyte is injected, and the gas chamber section includes adeformation part formed therein in a predetermined pattern to maintainshapes of the gas chamber inlet and a portion adjacent thereto.

Herein, the gas chamber inlet may be a part of the gas chamber section.

In addition, the deformation part may be formed in a concave or convexshape or is formed in a combination of the concave and convex shapes.

Further, the deformation part may have at least one of straight line,curve, polygonal, dot and circular shapes.

Further, the deformation part may control a flow of the electrolyte.

Further, the deformation part may be formed by insert molding.

According to another aspect of the present invention, there is provideda method of manufacturing a secondary battery, including: preparing apouch film which includes: a housing section configured to house anelectrode assembly; and a gas chamber section formed integrally with thehousing section and configured to discharge a gas generated by reactingan electrolyte with the electrode assembly to an outside, forming adeformation part in a predetermined pattern in the gas chamber section,housing the electrode assembly in the housing section, injecting theelectrolyte through a gas chamber inlet formed on one side of the gaschamber section, discharging a gas generated by the reaction between theelectrolyte and the electrode assembly to the gas chamber section side,and removing the gas chamber section and sealing the housing section.

Herein, a plurality of deformation parts may be formed in thepredetermined pattern.

In addition, the deformation part of the predetermined pattern may haveat least one of straight line, curve, polygonal, dot and circularshapes.

According to embodiments of the present invention, it is possible tomaintain the shape around the gas chamber inlet for injecting theelectrolyte so as to facilitate an injection of the electrolyte by thedeformation part.

In addition, it is possible to control a flow of the electrolyte by thedeformation part.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a fluoroscopic plan view of a pouch film having an electrodeassembly housed therein according to an embodiment of the presentinvention;

FIG. 2 is a cross-sectional view illustrating a gas chamber section ofthe pouch film according to the embodiment of the present invention;

FIG. 3 is a cross-sectional view of a gas chamber section of a pouchfilm according to another embodiment of the present invention; and

FIG. 4 is a flowchart illustrating a method of manufacturing thesecondary battery according to embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, specific embodiments of the present invention will bedescribed with reference to the accompanying drawings. The followingdetailed description is provided to contribute to a comprehensiveunderstanding of a method, apparatus, and/or system described herein.However, these embodiments merely illustrative examples, and the presentinvention is not limited thereto.

In descriptions of the embodiments of the present invention, publiclyknown techniques that are judged to be able to make the purport of thepresent invention unnecessarily obscure will not be described in detail.Referring to the drawings, wherein like reference characters designatelike or corresponding parts throughout the several views. In addition,the terms as used herein are defined by taking functions of the presentdisclosure into account and can be changed according to the custom orintention of users or operators. Therefore, definition of the termsshould be made according to the overall disclosure set forth herein.

In addition, the terminology used herein is for the purpose ofdescribing particular embodiments only and is not intended to limit thepresent invention thereto. As used herein, the singular forms “a,” “an”and “the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. It will be further understood thatthe terms “comprises,” “comprising,” “includes” and/or “including,” whenused herein, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

Further, it will be understood that, although the terms first, second,etc. may be used herein to describe various elements, components orsections, these elements, components or sections should not be limitedby these terms. These terms are only used to distinguish one element,component or section from another element, component or section. Thus, afirst element, component or section discussed below could be termed asecond element, component or section without departing from theteachings of the present invention.

Furthermore, directional terms such as “one side,” “the other side,”“upper,” “lower,” and the like are used in connection with theorientation of the disclosed drawings. Since the components of theembodiments of the present invention may be located in variousorientations, the directional terms are used for illustrative purposes,and are not intended to limit the present invention thereto.

FIG. 1 is a fluoroscopic plan view of a pouch film having an electrodeassembly housed therein according to an embodiment of the presentinvention. FIG. 1 is a view illustrating in such a way that an inside ofa pouch film 10 is viewed, and seeing through an upper side so as tomore clearly understand an inner space of the pouch film 10 for a clearunderstanding of the invention, but the upper side is not opened.

The pouch film 10 according to the embodiment of the present inventionmay include a housing section 200 and a gas chamber section 100integrally formed therewith.

The housing section 200 may provide a space in which an electrodeassembly 20 is housed. The electrode assembly 20 may mean a laminate inwhich electrodes such as a cathode and an anode are repeatedly laminatedwith a separation membrane (not shown) interposed therebetween.Therefore, the electrode assembly 20 may have a volume of apredetermined size or more. Thus, the housing section 200 may be formedby denting inward unlike other adjacent portions in the pouch film 10.As described below, after the electrode assembly 20 is housed in thehousing section 200, an electrolyte (not shown) may be injected.

The gas chamber section 100 may be a portion other than the housingsection 200 in the pouch film 10. Specifically, as illustrated in FIG.1, the gas chamber section 100 may be a portion formed by extending oneof portions forming the housing section 200 in a plane directionthereof. However, as illustrated in FIGS. 2 and 3, since the gas chambersection 100 serves as a gas passage, this section is not the portionformed by extending from only one surface of four surfaces of thehousing section 200, but may have a form of a tube which is formed byextending from one surface and disposing another surface parallel to theone surface with being spaced apart therefrom, thus to allow a gas to bedischarged to an outside.

The gas chamber section 100 may include a gas chamber inlet 110 and agas chamber passage 120.

The gas chamber inlet 110 of the pouch film 10 may be a portion intowhich the electrolyte is injected during injecting the electrolyte intothe housing section 200 of the pouch film 10. The gas chamber inlet 110may vary in a size depending on a device for supplying the electrolyte,thus it is not limited to the portion indicated as illustrated inFIG. 1. The device for supplying the electrolyte may be directlyconnected to the pouch film 10, or indirectly connected thereto througha separate configuration such as a tube to inject the electrolyte intothe housing section 200.

In addition, the gas chamber inlet 110 may be a portion from which a gasgenerated during injecting the electrolyte into the electrode assembly20 then pre-charging is discharged to the outside.

The gas chamber passage 120 may be a connection passage through which agas generated by a reaction between the electrolyte and the electrodeassembly 20 is discharged after the electrode assembly 20 is housed inthe housing section 200. Therefore, the gas chamber passage 120 may be aportion which is formed by extending a part of portions that do notcorrespond to the housing section 200 of the pouch film 10 by apredetermined length or more.

The gas chamber inlet 110 and the gas chamber passage 120 may beintegrally formed. Herein, these terms may be arbitrarily dividedaccording to functions performed by these parts for a clearunderstanding of the invention. The gas chamber inlet 110 of the gaschamber section 100 may be not only a portion in which the device forinjecting the electrolyte, or the like can be connected in communicationwith the outside, but also a portion from which the gas generated bypre-charging is discharged while being in contact with the outside, andthe gas chamber passage 120 may be a portion that serves as a passagewhen the electrolyte flows into the housing section 200 within the pouchfilm 10 and the gas generated during the pre-charging is discharged.

The gas chamber section 100 may have a deformation part 121 formedtherein in a predetermined pattern. Specifically, the gas chamberpassage 120 may include the deformation part 121 formed in thepredetermined pattern, and the deformation part 121 may be formedadjacent to the gas chamber inlet 110 so as to maintain the shapethereof. The deformation part 121 included in the gas chamber passage120 may perform various functions.

The deformation part 121 may serve to maintain the shapes of the gaschamber inlet 110 and a portion adjacent to the gas chamber inlet 110.Since the pouch film 10 is made of a metal material having excellentelongation, a rigidity thereof may not be strong. Therefore, it may bedeformed even by a small external force applied thereto.

For example, the electrolyte may move through the gas chamber inlet 110and the gas chamber passage 120 to fill the housing section 200. When alarge amount of the electrolyte inflows into the pouch film 10 at a timeor inflows in a moment at a high speed, a case, in which the gas chamberinlet 110 side is excessively opened due to the pressure applied to thepouch film 10 by the electrolyte, may occur. When the gas chamber inlet110 side is excessively opened, the electrolyte may flow down withoutbeing completely injected into the housing section 200.

Therefore, during injecting the electrolyte through the deformation part121 of the predetermined pattern, the deformation part 121 may serve tomaintain the shapes of the gas chamber inlet 110 and the portionadjacent to the gas chamber inlet 110.

In addition, the deformation part 121 may control a flow of theelectrolyte. Controlling the flow of the electrolyte may meancontrolling a direction in which the electrolyte flows. In addition, itis not necessary to mean only the direction in which the electrolyte isinjected into the pouch film 10.

For example, the deformation part 121 having a curved shape may preventthe electrolyte from splashing to the outside in a moment or theelectrolyte from flowing out of the pouch film 10 even if a large amountof the electrolyte inflows into the pouch film 10 side at a time.

In addition, when additionally injecting the electrolyte while thehousing section 200 is filled with the electrolyte up to a level, acase, in which the electrolyte contained in the housing section 200 mayslop or flow out of the housing section 200 while slopping due to amovement of the additionally injected electrolyte, may occur. In such acase, when forming the deformation part 121 on a portion of the gaschamber section 100 adjacent to the housing section 200 in a directionopposite to a space in which the housing section 200 is formed, it ispossible to prevent the electrolyte from flowing backward.

The deformation part 121 may be a portion in which the pouch film 10 isdeformed. As a method of deformation, it is possible to use deformationby heat, deformation in a form of changing a thickness or material of apart of the pouch film 10, deformation such as adding a substance, orthe like, but it is not limited thereto. However, it is preferable thatthe deformation part 121 is formed through insert molding. The reason isthat the insert molding may be more advantageous in terms of controllingthe size of the deformation part, or the like than the deformation byheat, and in the case of deformation such as changing a material oradding a substance, portions to be subsequently used as the secondarybattery and portions forming the gas chamber section 100 should be madeusing different materials or works from each other, such that additionalprocessing may be required.

The gas chamber section 100 may be a portion which is removed aftercompletely releasing the gas generated by the reaction between theelectrode assembly 20 and the electrolyte when manufacturing thesecondary battery. The purpose of this section is to minimize the sizeof the space occupied by the pouch film 10 in terms of an energy densityof the secondary battery. FIG. 1 illustrates that an advancing directionof the electrolyte during injecting the electrolyte and a dischargedirection of the gas generated during the pre-charging are opposite toeach other, and the deformation part 121 is perpendicular to thesedirections, but it is not limited thereto. The deformation part 121 maynot be parallel to the advancing direction of the electrolyte and thedischarge direction of the gas generated during the pre-charging. Theconfiguration in which the deformation part 121 is not parallel to theabove directions may not necessarily mean that the deformation part 121is formed so as not to be parallel to these directions.

For example, the deformation part 121 may be formed in a broken lineshape rather than a straight line shape, and may be formed in a curvedshape. That is, when describing based on FIG. 1, the straightline-shaped deformation part 121 may be replaced with the broken line orcurve-shaped deformation part. Although the deformation part 121 is notperpendicular to the traveling direction and the discharge direction ofthe gas generated during the pre-charging even when forming in thebroken line or curved shape, the deformation part 121 may perform thefunction of maintaining the shape of the gas chamber inlet 110 in orderto smoothly discharge the gas generated during the pre-charging.

FIG. 2 is a cross-sectional view illustrating the gas chamber section ofthe pouch film according to the embodiment of the present invention.

The deformation part 121 of the predetermined pattern may be formed in aconcave shape, a convex shape, or a combination of the concave andconvex shapes.

FIG. 2 shows that the concave shape and the convex shape are formedtogether, but it is not limited thereto, and the deformation part may beformed only in the concave shape, and the deformation part may be formedonly in the convex shape.

Forming deformation parts 121 and 121′ in a concave or convex shapemeans that the pouch film 10 is dented or extended to an outer side ofthe pouch film 10 toward the passage through which the gas generated bythe reaction between the electrolyte and the electrode assembly 20 movesto the outside.

FIG. 2 is merely one example to show that each of the deformation parts121 and 121′ may have different depths in which they are dented orexpanded, and that the shapes of the deformation parts 121 and 121′ mayhave both concave and convex. Therefore, the deformation parts 121 and121′ may be formed in such a way that one pattern is repeated or aplurality of patterns are arranged without periodicity.

FIG. 3 is a cross-sectional view of a gas chamber section of a pouchfilm according to another embodiment of the present invention.

A deformation part 122 formed in a predetermined pattern may have atleast one of straight line, curve, dot, polygonal and circular shapes.

A plurality of deformation parts 122 and 122′ may be formed in a gaschamber passage 120. In addition, the plurality of deformation parts 122and 122′ may be formed in such a way that one or more patterns repeatedto have a certain periodicity, or a plurality of patterns are arrangedwithout periodicity.

Having a straight or curved shape may mean that the deformation part isformed to have a continuous line shape so as to be oriented in atransverse or longitudinal direction on the pouch film 10.

The dot shape may mean a shape in which the deformation parts areembossed on the pouch film 10. Therefore, the pouch film 10 may have astructure for strengthening the gas chamber section 100 by formingseveral to several tens of dot-shaped deformation parts thereon.

The circular and polygonal-shaped deformation parts may literally mean ashape in which one or more circles or polygons are formed on the pouchfilm 10. There is no limit to the size of the circle or polygon.

In the case of having the above-described shape, since the deformationpart may be concavely or convexly formed in the pouch film 10, it cannotbe seen as a separate shape from the deformation part illustrated inFIG. 2, and the deformation part having the dot and circular shapescannot be also seen as a separate shape at all.

The division of terms with respect to the various shapes in the presentdisclosure is not intended to limit the shapes meant by each term, butfor the purpose of clear understanding of the invention.

FIG. 4 is a flowchart illustrating a method of manufacturing thesecondary battery according to embodiments of the present invention.

A secondary battery may be manufactured using the pouch film 10according to the embodiments of the present invention.

Specifically, the secondary battery may be manufactured using the pouchfilm 10 which includes the housing section 200 for housing the electrodeassembly 20 and the gas chamber section 100 which may be integrallyformed with the housing section 200 to discharge a gas generated by thereaction between the electrode assembly 20 and the electrolyte to theoutside.

More specifically, it is possible to manufacture a secondary battery bythe steps of: forming the housing section 200 in the pouch film (S1),housing the electrode assembly 20 in the housing section 200 (S2),forming the deformation part 121 in the gas chamber section 100 (S3),injecting an electrolyte (S4), discharging the gas generated by thereaction between the electrode assembly 20 and the electrolyte (S5), andremoving the gas chamber section 100 from the pouch film (S6).

However, the processes illustrated in FIG. 4 are just one example, andit is not necessary for each step to proceed in the order as illustratedin FIG. 4. That is, the order of the manufacturing method may be changedwithin a scope of being easily performed by those skilled in the art.

For example, the processes of steps S1 and S2 may be performed after theprocess of step S3 is preceded, or the processes may be performed in anorder of steps S1, S3 and S2. This change in the order may not affectthe effects of the invention.

The housing section 200 may be formed in the pouch film 10 through aforming process such as a pressing process. A space in which theelectrode assembly 20 is housed may be formed by the forming process.

The deformation part 121 may be formed in the gas chamber section 100through a molding process such as a pressing process or a notchingprocess for forming a notch. Specifically, the deformation part 121 maybe formed by a deep drawing method using a specific type of press, ormay be formed by cutting out a certain portion of the film to form anotch.

As described above, the method of forming the deformation part 121 isnot limited.

During injecting the electrolyte, a gas may be generated by reacting theelectrolyte with the electrode assembly 20. When forming the secondarybattery by sealing without removing the gas, or sealing immediatelyafter injecting the electrolyte, the secondary battery may swell. Whenthe secondary battery swells, it may be disadvantageous in terms of theenergy density, and the pouch film 10 may be easily broken even in asmall external impact. Therefore, it is preferable that the secondarybattery is manufactured by sealing the pouch film 10 after the gasgenerated by sufficiently reacting the electrolyte with the electrodeassembly is discharged and no more gas is generated.

The gas chamber section 100 may serve as a passage for removing the gasas described above. In addition, the electrolyte may be injected throughthe gas chamber inlet 110 of the gas chamber section 100. In this case,the deformation part 121 formed in the gas chamber passage 120 maycontrol the direction in which the electrolyte is injected to make theelectrolyte smoothly flow during injecting the electrolyte. In addition,the deformation part 121 may also serve to prevent the electrolyte fromflowing backward to the gas chamber passage 120 even when the housingsection 200 is fully filled with the electrolyte.

The gas chamber section 100 may be removed when manufacturing thesecondary battery. Since the secondary battery is important in terms ofthe energy density, after the gas generated by the reaction between theelectrolyte and the electrode assembly 20 is removed, if the gas chambersection 100 is left as it is, the space occupied by the secondarybattery may be increased and the weight may also be increased, such thatit is preferable to remove the gas chamber section 100.

Although the representative embodiments of the present invention havebeen described in detail, it will be understood by persons who have acommon knowledge in the technical field to which the present inventionpertains that various modifications and variations may be made thereinwithout departing from the scope of the present invention. Accordingly,the scope of the present invention should not be limited to theembodiments, but be defined by the appended claims as well asequivalents thereof.

DESCRIPTION OF REFERENCE NUMERALS

-   -   10: Pouch film    -   20: Electrode assembly    -   100: Gas chamber section    -   110: Gas chamber inlet    -   120: Gas chamber passage    -   121: Deformation part    -   122: Deformation part

What is claimed is:
 1. A pouch film comprising: a housing sectionconfigured to provide a space in which an electrode assembly is housed;and a gas chamber section formed with the housing section and configuredto discharge a gas generated by reacting an electrolyte with theelectrode assembly to an outside, wherein the gas chamber sectioncomprises a gas chamber inlet formed on one side thereof so that theelectrolyte is injected, the gas chamber section includes a deformationpart a) formed therein in a predetermined pattern and b) extending fromthe gas chamber inlet in a longitudinal direction toward the housingsection, and the deformation part is communicable along the longitudinaldirection from the gas chamber inlet towards the housing section.
 2. Thepouch film according to claim 1, wherein a cross section of thedeformation part extending along the longitudinal direction from the gaschamber inlet includes sections extending partially towards a center ofthe deformation part.
 3. The pouch film according to claim 2, whereinthe cross section of the deformation part also includes sectionsextending partially away from the center of the deformation part.
 4. Thepouch film according to claim 3, wherein the deformation part isunobstructed along a mid-plane of the cross section.
 5. The pouch filmaccording to claim 4, wherein the cross section is comprised of convexand concave protrusions which do not extend to the mid-plane.
 6. Thepouch film according to claim 1, wherein the gas chamber section isformed integrally with the housing section
 7. The pouch film accordingto claim 1, wherein the gas chamber inlet extends from the deformationpart and communicates with the deformation part so that the electrolyteis injected through the gas chamber inlet into the electrode assembly.8. The pouch film according to claim 1, wherein the deformation part isformed in a predetermined pattern to maintain a shape of the gas chamberinlet.
 9. The pouch film according to claim 1, wherein the deformationpart is formed in a concave or convex shape or is formed in acombination of the concave and convex shapes.
 10. The pouch filmaccording to claim 1, wherein the deformation part has at least one ofstraight line, curve, polygonal, dot and circular shapes.
 11. The pouchfilm according to claim 1, wherein the deformation part controls a flowof the electrolyte.
 12. The pouch film according to claim 1, wherein thedeformation part is formed by insert molding.
 13. The pouch filmaccording to claim 1, wherein the predetermined pattern of thedeformation part comprises one pattern repeated in the longitudinaldirection.
 14. The pouch film according to claim 1, wherein thepredetermined pattern of the deformation part comprises a plurality ofpatterns arranged in the longitudinal direction without periodicity. 15.The pouch film according to claim 1, wherein the predetermined patternof the deformation part comprises a continuous line shape.
 16. The pouchfilm according to claim 1, wherein the predetermined pattern of thedeformation part is embossed thereon.
 17. The pouch film according toclaim 1, wherein the gas chamber inlet is a part of the gas chambersection.
 18. The pouch film according to claim 1, wherein thedeformation part maintains the shape of the gas chamber inlet and aportion adjacent thereto.
 19. A pouch film comprising: a housing sectionconfigured to provide a space in which an electrode assembly is housed;and a gas chamber section formed with the housing section and configuredto discharge a gas generated by reacting an electrolyte with theelectrode assembly to an outside, wherein the gas chamber sectioncomprises a gas chamber inlet formed on one side thereof so that theelectrolyte is injected, the gas chamber section includes a deformationpart formed therein in a predetermined pattern to maintain a shape ofthe gas chamber inlet and a portion adjacent thereto, and the gaschamber inlet extends from the deformation part and communicates withthe deformation part so that the electrolyte is injected through the gaschamber inlet into the electrode assembly.
 20. The pouch film accordingto claim 19, the deformation part is communicable along a longitudinaldirection of the deformation part from the gas chamber inlet towards thehousing section.